The development of plasmid vectors useful for recombinant DNA genetics among microorganisms is well known. The prior art efforts involving recombinant gentic manipulation of plasmids for expressing various genes have centered on Escherichia coli (E. coli) as the host organism. However, there are certain limitations regardng such use of E. coli and, thus it would be desirable to be able to use host microorganisms other than E. coli, as for example human cell lines, in recombinant gentic manipulations.